Radeon HD 4770 vs Radeon HD 7850

Intro

Compare those specifications to the Radeon HD 7850, which features a core clock speed of 860 MHz and a GDDR5 memory speed of 1200 MHz. It also makes use of a 256-bit bus, and makes use of a 28 nm design. It is made up of 1024 SPUs, 64 Texture Address Units, and 32 Raster Operation Units.

Display Graphs

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Power Usage and Theoretical Benchmarks

Power Consumption (Max TDP)

Radeon HD 4770		80 Watts
Radeon HD 7850		130 Watts
	Difference: 50 Watts (63%)

Memory Bandwidth

Performance-wise, the Radeon HD 7850 should theoretically be quite a bit superior to the Radeon HD 4770 overall. (explain)

Radeon HD 7850		153600 MB/sec
Radeon HD 4770		51200 MB/sec
	Difference: 102400 (200%)

Texel Rate

The Radeon HD 7850 is quite a bit (more or less 129%) faster with regards to anisotropic filtering than the Radeon HD 4770. (explain)

Radeon HD 7850		55040 Mtexels/sec
Radeon HD 4770		24000 Mtexels/sec
	Difference: 31040 (129%)

Pixel Rate

If using a high resolution is important to you, then the Radeon HD 7850 is superior to the Radeon HD 4770, by a large margin. (explain)

Radeon HD 7850		27520 Mpixels/sec
Radeon HD 4770		12000 Mpixels/sec
	Difference: 15520 (129%)

Please note that the above 'benchmarks' are all just theoretical - the results were calculated based on the card's specifications, and real-world performance may (and probably will) vary at least a bit.

Price Comparison

Specifications

Memory Bandwidth: Memory bandwidth is the max amount of data (in units of megabytes per second) that can be transferred across the external memory interface in one second. The number is worked out by multiplying the card's bus width by its memory speed. In the case of DDR type RAM, it must be multiplied by 2 once again. If it uses DDR5, multiply by 4 instead. The higher the memory bandwidth, the better the card will be in general. It especially helps with anti-aliasing, High Dynamic Range and high resolutions.

Texel Rate: Texel rate is the maximum amount of texture map elements (texels) that are processed per second. This number is worked out by multiplying the total number of texture units of the card by the core clock speed of the chip. The better the texel rate, the better the video card will be at texture filtering (anisotropic filtering - AF). It is measured in millions of texels in a second.

Pixel Rate: Pixel rate is the most pixels that the graphics chip can possibly write to its local memory in a second - measured in millions of pixels per second. The number is calculated by multiplying the number of Raster Operations Pipelines by the the core speed of the card. ROPs (Raster Operations Pipelines - aka Render Output Units) are responsible for drawing the pixels (image) on the screen. The actual pixel rate also depends on quite a few other factors, especially the memory bandwidth of the card - the lower the bandwidth is, the lower the potential to get to the max fill rate.